Method of drawing metal



Patented May 22,

TES

PATENT OFFICE METHOD OF DRAWING METAL Robert M. Chesney, Warren, Ohio,assignor to The Youngstown Pressed Steel Company, Warren, Ohio, acorporation of Ohio Application January 14, 1933, Serial No. 651,820

3 Claims.

This invention relates to improvements in methods of drawing metal and,more especially, the drawing of relatively deep rectangular or squaredepressions in sheet metal to form receptacles, such as, sinks, washbasins, tubs, and

the like.

When a rectangular or square shape is drawn in sheet metal to form arectangular receptacle by the ordinary methods, the receptacle sides orside walls are ordinarily bulged due to excess metal.

Heretofore, it has been customary to draw a rectangular receptacle alittle undersize and then expand its side walls sideways in order toremove the bulge. successful.

This, however, has not always proven One of the features of my inventionis to provide a method for straightening the bulged sides ordinarilyformed when making rectangular or square deep-drawn sheet metalreceptacles.

In general, in the practice of my invention, a

receptacle shell having is first d1 awn from a a flange or marginal edgesheet metal blank a little shallow by the ordinary method. In otherwords,

the shell is not quite as or receptacle should be.

deep as the finished shape The shell is then placed in a die which isprovided with a hold-down ring that is serrated. A ram plate thatcarries another serrated hold-down ring is then moved verticallydownward and the hold-down rings the serrated portions of grip theflange or marginal edge of the receptacle and hold it rigidly in place.In the ordinary drawing process, these hold-down ring surfaces aresmooth and the marginal edge or flange of the receptacle is allowed toslide between the hold-down rings; but in the practice of my invention,edge of the partially tight, and, therefore,

the serrations hold the marginal formed receptacle perfectly enable thedie punch on the ram to stretch the main body or side walls of thereceptacle and draw out the excess metal at the bulge, making thereceptacle side walls straight and parallel.

The practice of my the accompanying drawing, in which:-

Figure 1 is a vertical sectional view of a drawn tub or receptacle withthe bulged sides left therein after the ordinary drawing ordinarilyoperation;

invention is illustrated in deep- Fig. 2 is a vertical sectional viewshowing one form of apparatus which may be used for stretching'the sidesof the receptacle shown in Fig. 1 to remove the bulge; and

Fig. 3 is a view simila pleted tub or receptac sides removed.

r to Fig. 1, showing a comle with the bulges in the Similar numeralsrefer to corresponding parts throughout the drawing.

In carrying out the improvedmethod, an unfinished deep-drawn sheet metalreceptacle having inwardly bulged side walls extending between 0 itsmarginal edge and bottom wall, such as shown in Fig. 1, is drawn in theusual manner from a sheet metal blank.

It is to be understood that the inwardly bulged receptacle shown in Fig.1 represents an article somewhat undersize in an unfinished state. Thatis,-the depression is drawn a little shallow.

The unfinished receptacle shown in Fig. 1 is then placed in apparatus,such as shown in Fig. 2, which may include a hold-down ring 10, pro-vvided with serrations 10a on its undersurface adapted to cooperate withserrations 11b in the cooperating hold-down ring 11 carried by a ramplate.

The receptacle to be made, for example a tub, comprises a bottom wall12, rectangular sides or side walls 13 and the flange or marginal edge14 extending outwardly from the upper ends of the side walls 13. Thestretching apparatus shown in Fig. 2, also includes a ram or male die 15operating in a female die 16.

After the unfinished receptacle of Fig. 1 is placed in the apparatusshown in Fig. 2, the hold-down ring 10 is moved down toward thehold-down ring 11, so that the flange or'marginal edge 14 of thereceptacle is located between and gripped by the serrations 10a and 11bof the hold-down rings 10 and 11. The ram 15 is then lowered intocontact with the bottom wall 12 and thereafter moved or forceddownwardly to the position shown in Fig. 2, to pull or stretch the sidesor side walls 13 of the receptacle. This stretching operation removesthe bulges shown in Fig. 1 and makes the sides or side walls of thefinished article straight and parallel, as shown in Fig. 3.

While I have shown and described certain embodiments of my invention, itis to be understood that it is capable of many modifications. Changes,therefore, in the construction and arrangement may be made withoutdeparting from the spirit and scope of the invention as disclosed in theappended claims, in which it is my intention to claim all noveltyinherent in my invention as broadly as permissible, in view of the priorart.

What I regard as new, Letters Patent, is:

1. The method of straightening bulged side walls extending between themarginal edge and and desire to secure by bottom wall of a deep drawnrectangular sheet metal receptacle, which includes the steps 01'.

drawn rectangular sheet metal receptacle, which includes the steps ofdeep drawing a rectangular depression in a sheet metal blank to producean unfinished receptacle having bulged side walls extending between abottom wall and a marginal edge, then gripping the marginal edge of thereceptacle to hold said marginal edge rigidly in place, and then forcingthe bottom wall downwardly to stretch and straightenthe bulged sidewalls between the marginal edge and bottom wall while gripping saidmarginal edge.

3. The method 0! making a deep drawn rectangular sheet metal receptaclehaving a bottom wall, straight and parallel rectangular side walls, anda marginal edge extending outwardly from the upper ends of said sidewalls; which includes the steps of deep drawing a rectangulardepressionin a sheet -metal blank to form an unfinished receptacle having inwardlybulged rectangular side walls extending between a bottom wall and amarginal edge, then gripping the marginal edge of the receptacle to holdsaid marginal edge rigidly in place, and then stretching said bulgedside walls between the bottom wall and rigidly held marginal edge tostraighten and true the same.

ROBERT M. CHESNEY.

